In-cell touch type liquid crystal display device

ABSTRACT

An in-cell touch type liquid crystal display device includes a touch line and a dummy touch line along a direction between neighboring pixel electrodes on a first passivation layer; a second passivation layer on the touch line and the dummy touch line; and common electrodes separated from one another in respective touch blocks, and each including first openings corresponding to each pixel region and a second opening corresponding to the touch line, wherein a connection pattern extending over a gate line from a side of the touch line at an inner region of the touch block is connected to a common electrode through a touch contact hole, and wherein an open portion is between the touch line and the dummy touch line.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 14/584,020, filed on Dec. 29, 2014, which claims priority from Korean Patent Application No. 10-2014-0111791, filed on Aug. 26, 2014, all of which are hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device (LCD), and more particularly, to an in-cell touch type LCD.

2. Discussion of the Related Art

Recently, LCDs have been spotlighted as next generation high-tech display devices of low power consumption, good portability, high added value and the like.

Among the LCDs, active matrix type LCDs are widely used, which includes a thin film transistor (TFT) in each pixel.

The LCD is applied to various appliances such as TV, projector, mobile phone and PDA, and the appliances have a touch function to touch a screen and conduct an operation.

An LCD having a touch function embedded therein is referred to as an in-cell touch type LCD.

The in-cell touch type LCD includes gate and data lines, and additionally, touch blocks to sense a touch and touch lines connected to the touch blocks.

In the in-cell touch type LCD, a common electrode is supplied with a common voltage for a display period to display an image. The common electrode functions as a touch electrode to sense a touch for a non-display period not to display an image.

Accordingly, when a user touch a touch region, for example, using a user's finger, a touch capacitance is produced between common electrodes which are separately formed at respective touch blocks. A touch position is detected by comparing the touch capacitance by the user's touch with a reference capacitance, and an operation according to the touch position is conducted.

In this regard, by comparing the touch capacitance with the reference capacitance, a coordinate where the user's touch happens is recognized, and then an operation corresponding to the coordinate is conducted.

Accordingly, a touch line, which transmits change of capacitance of a common electrode formed at each touch block to a sensing circuit portion that is located at a non-display region or printed circuit board, is required. Since the touch line is connected to the common electrode, the touch line cannot be formed at the same layer as the common electrode.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an in-cell touch type liquid crystal display device (LCD) that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide an in-cell touch type LCD that can compensate for a load difference between a gate line at an inner region of a touch block and a gate line at a boundary region of a touch block and improve display quality.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. These and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, an in-cell touch type liquid crystal display device includes gate and data lines crossing each other at a boundary of a pixel region on a substrate which includes a plurality of touch block each including a plurality of pixel regions; a thin film transistor in each pixel region and connected to the gate and data lines; a pixel electrode in the pixel region connected to the thin film transistor; a first passivation layer on the pixel electrode; a touch line and a dummy touch line along a direction between neighboring pixel electrodes on the first passivation layer; a second passivation layer on the touch line and the dummy touch line; and common electrodes separated from one another in respective touch blocks, and each including first openings corresponding to each pixel region and a second opening corresponding to the touch line, wherein a connection pattern extending over the gate line from a side of the touch line at an inner region of the touch block is connected to the common electrode through a touch contact hole, and wherein an open portion is between the touch line and the dummy touch line.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a view illustrating a structure of touch blocks of an in-cell touch type LCD according to a first embodiment of the present invention;

FIG. 2 is a view illustrating an in-cell touch type LCD according to a first embodiment of the present invention;

FIGS. 3A and 3B are views illustrating an inner region and a boundary region of a touch block of an in-cell touch type LCD according to a first embodiment of the present invention, respectively;

FIGS. 4 and 5 are views illustrating an inner region and a boundary region of a touch block of an in-cell touch type LCD according to a first embodiment of the present invention, respectively;

FIG. 6 is a graph illustrating a brightness difference between a pixel region at an inner region of a touch block and a pixel region at a boundary region of a touch block according to a first embodiment of the present invention;

FIG. 7 is a view illustrating an in-cell touch type LCD according to a first embodiment of the present invention;

FIG. 8 is a view illustrating a structure of touch blocks of an in-cell touch type LCD according to a second embodiment of the present invention;

FIG. 9 is a view illustrating an inner region of a touch block of an in-cell touch type LCD according to a second embodiment of the present invention; and

FIG. 10 is a view illustrating a boundary region of a touch block of an in-cell touch type LCD according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The same reference numbers may be used throughout the drawings to refer to the same or like parts.

First Embodiment

FIG. 1 is a view illustrating a structure of touch blocks of an in-cell touch type LCD according to a first embodiment of the present invention, FIG. 2 is a view illustrating an in-cell touch type LCD according to a first embodiment of the present invention, and FIGS. 3A and 3B are views illustrating an inner region and a boundary region of a touch block of an in-cell touch type LCD according to a first embodiment of the present invention, respectively. For the purpose of explanation, touch lines and common electrodes are omitted in FIG. 2, and touch lines are omitted in FIGS. 3A and 3B.

Referring to FIGS. 1 to 3B, the in-cell touch type LCD includes a display region including a plurality of pixel regions and a non-display region surrounding a display region.

A plurality of touch blocks TB are defined in the in-cell touch type LCD. The plurality of touch blocks TB each have a group of pixel regions neighboring to one another in a row direction and a column direction.

Gate lines 14 and data lines 16 are formed on a substrate and cross each other to define pixel regions.

Each pixel region includes a thin film transistor T connected to the corresponding gate and data lines 14 and 16, and a pixel electrode 18 connected to a drain electrode 17 of the thin film transistor T.

A touch line 190 a and a dummy touch line 190 b is formed at a boundary of the pixel region between the pixel electrodes 18. A passivation layer (not shown) is formed on the touch line 190 a, the dummy touch line 190 b and the pixel electrode 18.

Common electrodes 170 are formed on the passivation layer and in respective touch blocks TB, and are separated from one another. The common electrode 170 includes first openings 130 corresponding to each pixel region, and a second opening 135 corresponding to the touch line 190 a. The second opening 135 has a shape similar to the first opening 130.

The touch line 190 a is below the common electrodes 170. The touch line 190 a is connected to the common electrode 170 of the corresponding touch block TB through a touch contact hole TCH. The touch line 190 a is not connected to common electrodes 170 of touch blocks TB other than the corresponding touch block TB connected thereto. The touch line 190 a transmits a touch signal i.e., change of capacitance between neighboring common electrodes 170.

The dummy touch line 190 b is formed below the common electrodes 170 and is not connected to any common electrodes 170. In other words, the dummy touch line 190 b does not transmit a touch signal.

In this regard, the touch lines 190 a connected to the common electrodes 170 of the touch blocks TB are arranged substantially non-uniformly on an array substrate, thus capacitances between the common electrodes 170 and the touch lines 190 a become different, and thus display quality is degraded. To prevent this, the dummy touch lines 190 b are formed.

The touch line 190 a and the dummy touch line 190 b are not connected to each other, and an open portion OPEN between the touch line 190 a and 190 b is formed at a boundary portion of the touch block TB.

The common electrode 170 includes the first openings 130 in each pixel region, and the second opening 135 corresponding to the touch line 190 a and the dummy touch line 190 b. Further, the common electrode 170 includes a third opening 150 corresponding to the thin film transistor T, and a fourth opening 155 corresponding to the gate line 14.

The common electrode 170 formed at an inner region TIA of the touch block TB extends over a region “A” corresponding to the gate line 14 between the pixel electrodes 18 of neighboring pixel regions. Accordingly, portions of the common electrode 170 corresponding to the pixel regions in the touch block TB are connected to one another through the regions “A”.

Accordingly, a portion of the common electrode 170 corresponding to the pixel region in the inner region TIA of the touch block TB has an area greater than a portion of the common electrode 170 corresponding to the pixel region at a boundary region TBA of the touch block TB.

FIGS. 4 and 5 are views illustrating an inner region and a boundary region of a touch block of an in-cell touch type LCD according to a first embodiment of the present invention, respectively.

Referring to FIGS. 4 and 5, in the in-cell touch type LCD, a connection pattern 190 c extends from the touch line 190 a at the inner region TIA of the corresponding touch block TB, and is connected to the common electrode 170 through the touch contact hole TCH. The connection pattern 190 c may be located corresponding to the gate line 14. The open portion OPEN is formed between the touch line 190 a and the dummy touch line 190 b.

A first passivation layer is formed on the pixel electrode 18. The touch line 190 a and the dummy touch line 190 b are formed on the first passivation layer at the boundary of the pixel region. A second passivation layer is formed on the touch line 190 a and the dummy touch line 190 b. The common electrode 170 is formed on the second passivation layer.

The connection pattern 190 c extending from one side of the touch line 190 a is connected to the common electrode 170, and the touch line 190 a transmits a touch signal to a sensing circuit.

It is preferred, but not limited, that the touch line 190 a and the dummy touch line 190 b are formed of a low resistance metal material such as aluminum (Al) or copper (Cu) to prevent delay of a touch signal.

The touch line 190 a and the dummy touch line 190 b are formed at the boundary of the pixel region between the pixel electrodes 18. The touch line 190 a and the dummy touch line 190 b are not connected to a region between neighboring touch blocks TB. The open portion OPEN between the touch line 190 a and the dummy touch line 190 b is formed over the gate line 14 at the boundary portion TBA of the touch block TB.

FIG. 6 is a graph illustrating a brightness difference between a pixel region at an inner region of a touch block and a pixel region at a boundary region of a touch block according to a first embodiment of the present invention.

Referring to FIGS. 4 and 5, the common electrode 170 corresponding to the pixel region at the inner region TIA of the touch block TB has an additional area of the region “A”, compared with the common electrode 170 corresponding to the pixel region at the boundary region TBA of the touch block TB.

Further, at the inner region TIA of the touch block TB, the connection pattern 190 c extending over the gate line 14 (i.e., “Gate a” in FIG. 6) from the touch line 190 a is connected to the common electrode 170. However, at the boundary region TBA of the touch block TB, the open portion TBA is formed, and the connection pattern 190 c and the common electrode 170 are not formed.

Accordingly, at the inner region TIA of the touch block TB, due to a capacitance produced between the gate line “Gate a”, and the connection pattern 190 c and the common electrode at the region A, a load of the gate line “Gate a” at the inner region TIA of the touch block TB increases.

However, at the boundary region TBA of the touch block TB, the connection pattern 190 c and the common electrode 170 are not formed over the gate line 14 (i.e., “Gate b” in FIG. 6), thus no capacitance therebetween is produced, and thus a load of the gate line “Gate b” at the boundary region TBA of the touch block TB is less than that of the gate line “Gate a” at the inner region TIA of the touch block TB.

Accordingly, referring to FIG. 6, since an output of a gate signal applied to the gate line “Gate b” of a less load increases, a charging time of a data voltage of a pixel electrode of the pixel region at the boundary region TBA increases, and thus this pixel region is relatively high charged with a data voltage Vb.

However, since an output of a gate signal applied to the gate line “Gate b” of a greater load decreases, a charging time of a data voltage of a pixel electrode of the pixel region at the inner region TIA decreases, and thus this pixel region is relatively low charged with a data voltage Va.

Accordingly, the pixel region at the boundary region TBA of the touch block TB is seen brighter than the pixel region at the inner region TIA of the touch block, and thus display quality is degraded.

Second Embodiment

FIG. 7 is a view illustrating an in-cell touch type LCD according to a first embodiment of the present invention, and FIG. 8 is a view illustrating a structure of touch blocks of an in-cell touch type LCD according to a second embodiment of the present invention. For the purpose of explanation, touch lines and common electrodes are omitted in FIG. 7. Further, explanations of parts similar to parts of the first embodiment may be omitted.

Referring to FIGS. 7 and 8, the in-cell touch type LCD includes a display region including a plurality of pixel regions and a non-display region surrounding a display region.

A plurality of touch blocks TB are defined in the in-cell touch type LCD. The plurality of touch blocks TB each have a group of pixel regions neighboring to one another in a row direction and a column direction.

Gate lines 114 and data lines 116 are formed on a substrate and cross each other to define pixel regions.

Each pixel region includes a thin film transistor T connected to the corresponding gate and data lines 114 and 116, and a pixel electrode 118 connected to a drain electrode 117 of the thin film transistor T.

A touch line 290 a and a dummy touch line 290 b is formed at a boundary of the pixel region between the pixel electrodes 118. A passivation layer (not shown) is formed on the touch line 290 a, the dummy touch line 290 b and the pixel electrode 118.

Common electrodes 270 are formed on the passivation layer and in respective touch blocks TB, and are separated from one another.

The touch line 290 a is below the common electrodes 270. The touch line 290 a is connected to the common electrode 270 of the corresponding touch block TB through a touch contact hole TCH. The touch line 290 a is not connected to common electrodes 270 of touch blocks TB other than the corresponding touch block TB connected thereto. The touch line 290 a transmits a touch signal i.e., change of capacitance between neighboring common electrodes 270.

The dummy touch line 290 b is formed below the common electrodes 270 and is not connected to any common electrodes 270. In other words, the dummy touch line 190 b does not transmit a touch signal.

In this regard, the touch lines 290 a connected to the common electrodes 270 of the touch blocks TB are arranged substantially non-uniformly on an array substrate, thus capacitances between the common electrodes 270 and the touch lines 290 a become different, and thus display quality is degraded. To prevent this, the dummy touch lines 290 b are formed.

The touch line 290 a and the dummy touch line 290 b are not connected to each other with an open portion OPEN therebetween. The open portion OPEN is formed at a region other than a region of the gate line 114. In other words, the open portion OPEN is formed at the inner region TIA of the touch block TB.

Accordingly, a compensation pattern 290 d extending from the touch line 290 a and the dummy touch line 290 b is formed corresponding to the gate line 114 at a boundary region of the touch block TB. The compensation pattern 290 d are preferably formed to have the same shape as a connection pattern extending from the touch line 290 a at an inner region of the touch block TB.

FIG. 9 is a view illustrating an inner region of a touch block of an in-cell touch type LCD according to a second embodiment of the present invention, and FIG. 10 is a view illustrating a boundary region of a touch block of an in-cell touch type LCD according to a second embodiment of the present invention.

Referring to FIGS. 9 and 10, in the in-cell touch type LCD, a connection pattern 290 c extends from the touch line 290 a at the inner region TIA of the corresponding touch block TB, and is connected to the common electrode 270 through the touch contact hole TCH.

The connection pattern 290 c may be located corresponding to the gate line 114. The open portion OPEN is formed between the touch line 290 a and the dummy touch line 290 b.

The touch line 290 a is formed at the boundary of the pixel region and extends along a direction.

The common electrode 270 includes first openings 230 in each pixel region, and a second opening 235 corresponding to the touch line 290 a and the dummy touch line 290 b. Further, the common electrode 270 includes a third opening 250 corresponding to the thin film transistor T, and a fourth opening 255 corresponding to the gate line 114. The common electrodes 230 are separated by the fourth opening 255.

The common electrode 270 includes a third opening 250 corresponding to the thin film transistor T, and extends over the gate line 114 at the inner region TIA of the touch block TB.

The connection pattern 290 c extending from one side of the touch line 290 a is connected to the common electrode 270 through the touch contact hole TCH, and the touch line 290 a transmits a touch signal to a sensing circuit.

It is preferred, but not limited, that the touch line 290 a and the dummy touch line 290 b are formed of a low resistance metal material such as aluminum (Al) or copper (Cu) to prevent delay of a touch signal.

A first passivation layer is formed on the pixel electrode 118. The touch line 290 a and the dummy touch line 290 b are formed on the first passivation layer at the boundary of the pixel region. A second passivation layer is formed on the touch line 290 a and the dummy touch line 290 b. The common electrode 270 is formed on the second passivation layer.

The compensation pattern 290 d extends from one side of the touch line 290 a and the dummy touch line 290 b at the boundary region TBA of the touch block TB and corresponds to the gate line 114.

A separate distance between the common electrodes 270 at the boundary region TBA of the touch block TB may be reduced to about 2 um to prevent short-circuit between the common electrodes 270.

Accordingly, an area of the common electrode 270 over the gate line 114 at the boundary region TBA of the touch block TB may be almost equal to an area of the common electrode 270 over the gate line 114 at the inner region TIA of the touch block TB.

Accordingly, a load of the gate line 114 at the boundary region TBA of the touch block TB is equal to a load of the gate line 114 at the inner region TIA of the touch block TB, thus output waveforms of the gate lines 114 become equal and charging times of data voltages of pixel electrodes 118 becomes equal, and thus brightness of the pixel region at the inner region TIA of the touch block TB and brightness of the pixel region at the boundary region TBA of the touch block can become equal. Therefore, degradation of display quality can be prevented.

Further, the open portion OPEN between the touch line 290 a and the dummy touch line 290 b is formed outside a region of the gate line 114 at the boundary region TBA of the touch block TB.

The open portion OPEN is preferably formed below the gate line at the boundary region TBA of the touch block TB and between the pixel regions.

The open portion OPEN is formed outside the gate line at the boundary region TBA, and thus the compensation pattern 290 d extending from the dummy touch line 290 a can be formed over the gate line at the boundary region TBA.

In accordance with example embodiments, an in-cell touch type LCD may be provided that compensates for a load difference between a gate line at an inner region of a touch block and a gate line at a boundary region of a touch block and improves display quality. As described above, in the in-cell touch type LCD, the open portion between the touch line and the dummy touch line is formed outside the gate line at the boundary region of the touch block, and the compensation pattern, which has the same shape as the connection pattern at the inner region of the touch block is formed over the gate line at the boundary region of the touch block. Therefore, brightness of the pixel regions at the inner region of the touch block can be equal to brightness of the pixel region at the boundary region of the touch block, and thus display quality can be improved.

It will be apparent to those skilled in the art that various modifications and variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

What is claimed is:
 1. A display device, comprising: a plurality of common electrodes that include a first common electrode corresponding to a first touch block and a second common electrode corresponding to a second touch block; a touch line oriented in a first direction and connected to the first common electrode, the touch line not overlapping with the second common electrode; and a dummy touch line overlapping with the second common electrode and oriented in the first direction, the dummy touch line aligned with the touch line in the first direction but being disconnected from the touch line.
 2. The display device of claim 1, wherein the first common electrode corresponds to a first plurality of pixel regions and the second common electrode correspond to a second plurality of pixel regions.
 3. The display device of claim 1, wherein the dummy touch line and the touch line are disconnected in a region between the first common electrode and the second common electrode.
 4. The display device of claim 1, wherein the dummy touch line and the touch line are disconnected in a region that corresponds to the first common electrode.
 5. The display device of claim 1, wherein the dummy touch line and the touch line are in a same layer.
 6. The display device of claim 5, wherein the dummy touch line and the touch line are both in the same layer and on a passivation layer.
 7. The display device of claim 5, wherein the dummy touch line and the touch line are in a different layer than the plurality of common electrodes.
 8. The display device of claim 1, wherein the dummy touch line and the touch line are both comprised of a same metal material.
 9. The display device of claim 1, wherein the touch line overlaps with a first opening in the first common electrode, and the dummy touch line overlaps with a second opening in the second common electrode.
 10. The display device of claim 1, wherein the dummy touch line has a dummy compensation pattern extending from a side of the dummy touch line, the dummy compensation pattern extending over a gate line.
 11. The display device of claim 10, wherein the dummy compensation pattern extends over the gate line in a region between the first common electrode and the second common electrode.
 12. The display device of claim 10, wherein the touch line has a connection pattern extending from a side of the touch line over another gate line, the connection pattern connected to the first common electrode through a contact hole, and the compensation pattern has a substantially same shape as the connection pattern.
 13. The display device of claim 1, wherein the common electrodes are supplied with a common voltage during a display period for image display, and the common electrodes function as touch electrodes during a non-display period. 